To answer Joe's original question, the rear axle of the 6000 series AD trucks was rated at 13,000 lbs.
The rear wheel bearings used (thru '53) were GM part #144527 for the inner, and GM part #144525 for the outer. These are still good part numbers (at least they show up in a cross reference). An ACDelco lookup gives AC part #'s S612 and S615, respectively. Put those #'s into a search on
this ACDelco search page to see what vehicles they were used in. C3500's and P30's are in the list, among others.
Even if these are the same bearings used in the Dana 70HD, the Dana and AD hubs may be different enough in other dimensions as not to be interchangeable.
Addendum: The industry standard numbers for the wheel bearings mentioned above are 395CS/394CS inner, and 387/382 outer, with diameters of 2.625"/4.468" and 2.25"/3.875" respectively (cone bore/race outer dia.). Maybe these numbers can be used to compare to the Dana bearings.
